The present invention is with respect to a grooving or scoring unit, made up of a knife-edged wheel and a back-up part placed on the two sides of a moving web of paper being pulled along and transported by two rolls (of which at least one has a driving system) in, more specially, a folder having a folder blade for producing a second lengthways fold along the groove or score line in said web before the paper comes from the folder as folded products.
The grooving or scoring of paper webs at the positions of the second lengthways fold to be produced using a folder blade is responsible for more accurate or neater operation of the folder blade. In the prior art a separate grooving unit or station has been used placed upstream or downstream from the transport or nipper rolls. This makes the design of the system more complex, and takes up much space as is generally not to be desired.